High-quality electrical bicycles usually employ torque sensors for sensing a driver torque. If the driver desires support, an electric drive then proportionally amplifies the sensed driver torque. This results in a driving feel that is perceived as natural by the driver since a greater introduction of force takes place simultaneously with a greater support up to a maximum support. More cost-effective electrical bicycles frequently have only a pedal-speed sensor. Here, support by the electric drive is then rendered for the most part at a constant torque. This heavily restricts the metering ability of the motor torque, especially in high support stages. In addition, the patent document DE 102010017742 A1 discusses a method for actuating an electric drive of a bicycle, in which the driver torque is estimated. However, this method is therefore very imprecise so that support by the electric drive may lead to a poor driving feel.